Olive oil refining process



OLIVE 'OIL REFINING PROCESS Maria Ester Alessandrini, Rome,'and Fortunate Palazzo, Florence, Italy, assignors of one-third to Fondazione Emanuele Patemo, Rome, Italy No Drawing. ApplicationDecember 26, 1957 Serial No.'705,091

Claims priority, application Italy February 15, 1957 3 3 Claims. (Cl. 260-423) The present invention relates to a process to remove the residues of parathion (0,0-diethyl-O-paranitrophenylthiophosphate) from olive oils and from vegetal oils generally. w

The undoubted effectiveness of the parathion in the action against the olive fiy is well known, but it is also well known that residues of this insecticide, which is highly toxic also for the men and for the mammals generally, remain in a more or less high amount in theoils obtained from the oliveplantations treated with formulations based on said insecticide.

The tolerance limit of saidresidues, to an extent which may be considered as not'dangerous in the daily ingestion of amounts of oil which are commonly consumed, is still being discussed and the problem concerned is as yet under consideration by the health authorities throughout the world, and particularly in those countries, such as Italy, which are producers of olive oil.

The applicants have studied a system to remove these:

residues in the olive oils obtained both by pressing and by extraction, as well as in the vegetal oils generally.

To this purpose refining tests have been carried out on olive oils containing parathion residues in more or less high percents.

However, contrary to the results to be reasonably expected, the experiments, carried out by the commonly used methods removed only to a small extent the parathion from the oils submitted to these treatments, even when i the insecticide was present only in reduced amounts.

By the present invention, which will be later disclosed in its features and described in its details, it is possible to remove totally the parathion residues present in the oils even when in material amounts, (up to 200 p.p.m.)

and this with a high'yield of the finished product together solutions system;

(2) Decolourising by a mixture of fullers earths and decolourising charcoals;

(3) Deodorisation under vacuum by blowing steam in at different temperatures.

But, while as aforesaid, by the known refining processes it is possible only to remove a small portion of the amount of parathion contained in the oils (about20% of the initially present amount), the oil obtained according to the present invention is entirely free from parathion, even when said parathion is initially present in a relatively high amount.

The process is apt to remove the parathion residues contained in the oils up to 200 parts per million (p.p.m.)

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provided that the reactantis well preserved and therefore sufficiently active, and provided that all of the .prescrip tions which are described for the practice of the present invention are accurately complied with.

When oils containing high amounts of parathion, in

the range of 200 p.p.m. (which practically, however, are

never encountered) are treated according to this invention, small amounts of parathion might remain in the treated product, always less than 10 p.p.m., said residue being however totally removed by a second cycle of treatments. v I I The reactant, which is an alkali hydrosulphite, added before the neutralising step, determines the reduction of the parathionto the corresponding amino derivative which, in turn is partially hydrolized giving p'.amino phenol. Said p.amino-phenol remains partially dissolved in the oil, and partially in the soap solution.

Boththe amino derivative of thefparathion and the pamirio-phenol, are totally retained bythe common decolourising earths during the decolourising process. The other part of the molecule formed during the hydrolysis of the amino derivative of parathion, i.e. the sodium salt of the diethylthiophosphoric acid, is quickly transformed to the corresponding salt of the diethyl-phosphoric acid, and both these products are non-toxic for the mammals. Otherwise neither of these products is found in appreciable amount in the final oil, since these prod ucts remain dissolvedin the alkali-water phase. 1

The final oils resulting are s'urely' non-toxic since they contain no parathion and no decomposition derivative thereof. Furthermore, the, organoleptic"characters, as well as the physical and'chemical features of the oils treated according to thepres'ent invention are normal and equal to those of the 'same' oils when relfined-by the process as commonly practiced, i.e. with no addition of hydrosulphites.

The practice of this process will be disclosed hereinafter.

Under the industrial standpoint, the practical embodiment of thisprocess offers no difiiculty and presents no particular requirement in that use. may be made of the apparatus presently existing in the'oil art.

Furthermore, the process has a remarkable flexibility allowing said process to be easily adapted to the characteristics of the oils. Therefore, this process allows the treatment of the most different grades of oils.

. In this connection his to be noted that the acidity of the oils obtained by pressing and containing parathion, hardly goesbeyond 2% and that this process, as itwill be later described, may be applied to oils having'anaoidity The process according to this invention, apt to remove the parathion contained in the olive oils and in the vegetal oils generally, is carried out through the following steps:

(a) Washing of the raw oil.The oil is poured into a neutralising container provided with a stirrer and a coil for steam circulation, in the amount of about 5 of the useful volume of the container. The mass is heated under stirring up to a 94 C. temperature and then the mass is sprayed with water at C. in an amount equalling 10% by weight of the oil. The stirring is stopped and the mass is allowed to rest for a time interval from 1 to 3 hours.

([2) Addition of alkali hydr0sulphite.-After having discharged the washing water, the oil temperature is brought again to 94 C. and always under stirring, hot water is added at a temperature of 85-95 C. in the amount of 2-3 liters for each kg. of free acidity expressed as oleic acid, and then the reduction agent is added.

Any of the alkali hydrosulphites commercially available may beused, for instance those known under the trade names of: -Albite A, Albite-La; Blankit; 'Arostit Blanco; Clarite P.S.E.; Hydros, provided thatthe reactant is well preserved in a dry location and in a well closed container. i

The alkali hydrosulphite is to be used in the amount of 500 g. for each 100 kg. of oil to be treated. In a container, preferably a wooden container, provided with a mechanical stirrer, are placed as many liters of sodium hydroxide lye at 22-23 B. and as many kgs. of hydrosulphite as are requested by the oil and, under manual or mechanical stirring, the metered amount of hydrosulphite is gradually added.

The so obtained slurry is added to the oil already heated at 94 C. and under stirring which must be continued up to the end of the neutralising step.

(c) Neutralising step.After 10-15 minutes further water heated to 85-95" C. is added in the amount of 2-3 liters per each kg. of free acidity, expressed as oleic acid, of the oil, and soon after taking care of keeping the temperature of the oil at 94 C., 5 to in excess of the amount of sodium hydrate solution, at 22-24 B., stoichiometrically required by the oil to be neutralised is also added.

(d) Washing of the neutral oil.--After completion of the addition of the sodium hydroxide, the stirring is immediately interrupted and a decantation period is allowed for about three hours before beginning the washing steps, two or three in number, which are carried out with warm water at 85-95 C. at time intervals of one-two hours from each other, if the decantation is clean and quick, and with salted water (5-10% of common salt) in case the decantation occurs with some difiiculties.

(e) Decolourising step.--After the soap waters and the washing waters have been run out, the neutralised oil is carried to a common decolourising container, where, under vacuum and under stirring, the oil is first dried at 90-100" C., and then treated with decolourising earths and charcoals, amounting to 45% and 0.5%, respectively, based on the oil.

After about 30 minutes the product is filtered in press-filter provided with suitable cotton fabrics or the like.

We claim:

1. A process for the complete removal of parathion and residues thereof from olive oil containing same which comprises: (a) heating the olive oil under agitation to a temperature of about 94" C., (b) spraying the heated, and agitated mass with water at about 85 C., the weight of said water being about 10% of that of the oil, (0) allowing the resulting product to rest for a period of from 1 to 3 hours, (d) discharging the wash sprayed on the heated mass, (e) reheating the oil to a temperature of about 94 C., (f) adding water at a temperature of from to 95 C. to theheated oil under stirring, the amount of water added being about 2 to 3 liters per kilogram of free acidity expressed as oleic acid, (g) adding to the oil 'under agitation 500 grams of alkaline hydrosulphite for each kilograms of oil, (h) adding about- 2 to 3 liters per kilogram of free acidity, expressed as oleic acid, of water at a temperature of from 85 to 95 C., (1') adding to the thus-treated oil about 5 to 10% in excess of the amount of sodium hydrate solution at 22 to 24 B. stoichiometrically required to neutralize said oil, (j) decantingfor about 3 hours, (k) washing the decanted oil at least twice with water at from 85 to 95 C., said washings being separated from each other by an interval of from 1 to 2 hours, (I) discharging the wash water, (m) under stirring and reduced pressure drying the oil at a temperature of from 90 to 100 C., (n) contacting the dried oil with from 4 to 5% of decolorizing earth'and about 0.5% of charcoal, and (0) filtering the' oil. 5

-2.'In a process for the removal of parathion (0,0-diethyl-O paranitrophenyl thiophosphate) and residues thereof from olive oil containing same, said .process comprising the addition of substituents to the olive oil, the

improvement wherein two ofsaid substituents are alkali hydrosulphite and sodium hydrate and said addition is followed by decolorizing the resulting product with decolorizing earth and charcoal.

3. In a process for the removal of parathion (0,0- diethyl-O-paranitrophenyl-thiophosphate) and residues thereof from olive oil containing same, said process comprising water-washing the olive oil containing parathion,

sequentially adding substituents to the washed olive oil, decanting the product, washing the decanted product,

drying the resulting oil and decolorizing said resulting oil References Cited in the file of this patent UNITED STATES PATENTS 2,569,124 Christensen et al Sept. 25, 1951 2,684,971 Godfrey July 27, 1954 2,732,388 Sadler et a1. Jan. 24, '1956 

2. IN A PROCESS FOR THE REMOVAL OF PARATHION (O,O-DIETHYL-O - PARANITROPHENYL - THIOPHOSPHATE) AND RESIDUES THEREOF FROM OLIVE OIL CONTAINING SAME, SAID PROCESS COMPRISING THE ADDITION OF SUBSTITUENTS TO THE OLIVE OIL, THE IMPROVEMENT WHEREIN TWO OF SAID SUBSTITUENTS ARE ALKALI HYDROSULPHITE AND SODIUM HYDRATE AND SAID ADDITION IS FOLLOWED BY DECOLORIZING THE RESULTING PRODUCT WITH DECOLORIZING EARTH AND CHARCOAL. 